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The acid-base abnormalities in uremic patients on hemodialysis are well known. There is less awareness of the fact that during bicarbonate dialysis patients are simultaneously exposed to the four fundamental acid-base disorders. Attempts at compensation involving the respiratory system persist in the hours following hemodialysis. Furthermore, several landmark publications in addition to more recent papers clearly show that bicarbonate HD is only able to compensate for uremic acidosis through the elimination of surplus CO2 from dialysate via the lungs. The artificial kidney and lungs of the patient work together to ensure the efficiency of hemodialysis. Dialysate is a more acidic solution than the patient's blood and contains, in addition to oxygen and bicarbonate, at least twice the CO2 concentration of blood. The high dialysance of CO2 allows for its rapid diffusion from the dialysate to the blood compartment and can be a clinically relevant issue in patients with co-morbidities, especially respiratory disease. In such circumstances, hemodialysis may cause iatrogenic respiratory acidosis which, if not recognized, can require ventilatory assistance and advanced life support. Checking for such problems in a real life setting, such as an outpatient hemodialysis unit, is an important part of the nephrologists day-to-day work.

Purpose: Dialysis morbidity results partly from middle and large molecule retention, which is poorly removed by conventional hemodialysis (HD). The potential benefit of convective treatments could be the enhanced toxin removal over a wide molecular weight spectrum. This study aimed to evaluate cystatin C (cis), beta2-microglobulin (beta2-m) and C-reactive protein (CRP) removal behavior during hemodiafiltration reinfusion vs conventional low-flux HD (1.8 m2 low-flux polysulphone) (bicarbonate dialysis (BD)). The molecular weights of the substances evaluated in this study were as follows: cis = 13,300 daltons, beta2-m = 11,818 daltons, CRP = 160,000 daltons., Methods: Twelve patients on stable HD (six males, six females), were enrolled; six patients underwent BD and six patients underwent HFR. We measured arteriovenous serum cis, beta2-m and CRP levels, in three consecutive mid-week sessions at the following periods: pre/post-dialysis and after 60 min from the beginning of the session. At 60, 120 and 180 min of HFR, we collected the ultrafiltrate for cis, beta2-m, and CRP evaluation., Results: Cis, beta2-m and CRP mean values did not differ at pre-dialysis in the two groups. Pre/post- dialysis difference for cis in HFR vs BD was statistically significant (p=0.002) because cis reduced in HFR and increased in BD during the session. Beta2-m and CRP pre/post- dialysis differences in HFR vs BD were not significant. Cis clearance, measured 60 min after the beginning of the session was 34.2 +/- 20.1 mL/min in HFR and 24.8 +/- 18.4 mL/min in BD (p<0.05). beta2-m and CRP clearances did not differ among the treatments. Regarding the ultrafitrate concentrations during the HFR session, cis significantly decreased (2.5 +/- 0.6 mg/dL at 60 min and 2.0 +/- 0.4 mg/dL at 180 min; p=0.004), as well as beta2-m (21.5 +/- 12.9 mg/dL and 19.0 +/- 14.1 mg/dL, respectively; p=0.02). Ultrafiltrate CRP values, as expected, did not differ during HFR., Conclusions: This study demonstrated that cis, a middle molecule, is well depurated in HFR, while in BD it increases. Beta2-m, although better removed in the convective phase during HFR, does not demonstrate a removal difference in HFR and in BD. CRP, a large molecule, does not have significant removal. Since cis and beta2-m have almost the same molecular weight, why do they have a different depuration? We need further studies to evaluate if membranes can remove these molecules or if protein electrical charges or their stereoscopy enables their removal.

Physiological gallbladder contraction, delivering bile salts during meals, plays a key role in digestive mechanisms. A bicarbonate-alkaline water (Uliveto) shows a positive effect on gallbladder kinetics: so it may be useful in order to improve dyspepsia due to delayed gallbladder emptying.

The above study was intended to assess the effect of a bicarbonate sulfate alkaline water of medium mineral contents in long-distance runners during training. Several parameters relating to water-electrolyte and lactate-pyruvate metabolism, and to the patterns of serum enzymes of variable cellular localization were determined. Altogether twelve indices were taken into account. No significant changes were observed fron the start to the end of mineral water treatment. This goes to show that training was well balanced and did not impair the athletes' biochemical homeostasis. At the end of the treatment period, non negligible fluctuations of CCK and LDH were observed. This finding is not devoid of interest and deserves further study.

The Authors, helped by S.E.M., examine the validity of the sigillature, as prophilactic measure against the formation of carious process. Tests effectuated on 100 patients' teeth show this therapy efficaciousness.

Hemodialysis treatments with large surface area dialyzers were introduced in our dialysis unit since 1974. 129 uremic subjects were treated between September 1974 and August 1988. Age at start of high efficiency therapy ranged between 16 and 72 years; patients survival was: 95.3% at 1 year, 78.3% at 5 years, 65.8% at 10 years. At present 48 subjects are treated with this schedule. The key technical elements for implementation of such program include: high blood flow rates (greater than 300 ml/min), high surface area dialyzers (greater than 1.8 m2), bicarbonate as the buffer source. Traditionally, the rate of ultrafiltration was controlled by monitoring the TMP and the patients body weight, but in some case a preferred approach is the use of an automatic ultrafiltration control system. We conclude that, in a quite large dialysis population, an individualized short dialysis schedule may be safely applied for long time periods.

During this work through the total bacterial count and of the pseudomonas and the determination of the positive substances to Limulus Amebocyte Lysate test, bacterial pollution of the liquid bicarbonate concentrate has been determined together with the influence that preparation conditions and the entity of interval between the said preparation and utilization of concentrates have on it. Through the evaluation of the cardiac rate and the systemic arterial pressure, we have studied the influence of the bacterial pollution on the clinical of the patient. Analysing the obtained data we can point out that the liquid bicarbonate concentrate present an elevated degree of contamination which feels the effects of the production and storage procedures. The remark of inverse correlation between systemic arterial pressure and endotoxin level of the dialysate seems to reconfirm the importance of the bacterial contamination on the clinical of the patient.

The sequence of calculations that can be entered in the memory of a desk computer for the automatic calculation of acid base balance parameters using data obtained with Astrup's tonometric method is described. A statistical comparison is also made between manually obtained results and those obtained with computer assistance. For clinical purposes the comparison is satisfactory.